1. Field of the Invention
This invention relates to an electrical wiring distribution system, and more particularly to an electrical wiring distribution system for fill-on-slab or fill-on-grade floor constructions.
2. Description of the Prior Art
Floor structures are known which incorporate corrugated sheets laid in edgeoverlapped relation and supported on structural beams. Certain of the corrugated sheets include relatively wide channels which are enclosed by the addition of closure elements to provide electrical passageways. Header ducts are disposed above, extend transversely of the electrical passageways, and communicate with the electrical passageways. A covering layer of concrete is supported by the corrugated sheets. Outlet tubes provide access to the conductors in the electrical passageways and in the header ducts from the finished floor level. Such a floor structure is disclosed in U.S. Pat. No. 3,912,848 (LEE et al).
Cellular metal raceway sections are known which provide two parallel cells separated by an intermediate trough and wherein cover strips and chamber-defining members enclose the intermediate trough to form an additional unobstructed wiring passageway. The chamber-defining member comprises an enclosure which spans across the trough and the adjacent cells and communicates with the cells through openings in the cell crests. Outlet openings in the top wall of the enclosure provide access to the interior of the enclosure and to the trough from the finished floor level. A typical reinforced floor structure may contain a plurality of the cellular metal raceway sections arranged in spaced-apart generally parallel relationship. An electrical trench header may be provided which extends transversely across the tops of the metal cellular raceway sections and which communicates with the cells for distributing electrical wiring throughout the floor area. Such an arrangement is disclosed in U.S. Pat. No. 3,592,956 (FORK).
An electrical wiring distribution system for building floors is known which includes an uninterrupted main unit consisting of a metal cellular raceway section providing spaced-apart generally parallel main passageways and at least one laterally extending feeder unit consisting of a metal cellular raceway section providing spaced-apart generally parallel feeder passageways. A housing is provided which encloses a segment of the main unit and an end segment of the feeder unit. The housing is compartmented so as to restrict communication between each main passageway and a corresponding feeder passageway. Such an arrangement is disclosed in U.S. Pat. No. 3,453,791 (FORK).
The LEE et al '848 and the FORK '956 arrangements incorporate wiring passageways at two different levels and necessarily result in relatively thick floor structures.
In the FORK '791 arrangement, the vertical distance between the cover plate and the top of the main unit must be large to accommodate large diameter telephone wiring. Hence a relatively thick covering layer of concrete is required.